Electric circuit breaker



1932- H. TRENCHAM ET AL 1,391,070

ELECTRIC CIRCUIT BREAKER Filed April 30, 1931 2 Sheets-Sheet l L A? J IIi i F .I. I XI 2 I f 21 T7 3} L"'y Inventors: Henna Trencham, HerbertC. Heath, by m Their Attorne Dec. 13, 1932.

H. TRENCHAM ETAL 1, ,070

ELECTRIC CIRCUIT BREAKER Filed April 30, 1951 2 Sheets-Sheet 2IIIIIIIIIIIIIIIIIIIIIIIIII 1 Inventors: Henrg Trencham, Herbert C.Heath,

Patented Dec. 13, 1932" UNITED STATES PATENT OFFICE HENRY TRENCHAM, OFR'UISLIP, AND HERBERT C. HEATH, OF WEMBLEY, ENGLAND, ASSIGNORS T0GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC CIRCUITBREAKER Application filed April 30, 1931, Serial -No. 534,662, and inGreat Britain Kay 13, 1880.

Our invention relates to electric circuit breakers, more particularly tomechanism for effecting the tripping operationof circuit mechanismcausing opening movement 0 the circuit breaker. However, under certainopcrating conditions, as where the circuit must be cleared within a veryshort time, it may be desirable to introduce a direct acting trip so asto decrease the time of the tripping opera tion.

In accordance with the present invention,

' in a circuit breaker or a combination circuit breaker andfuse capableof being tripped open by the collapse of an operating toggle mechanismthe tripping impulse is transmitted directly to the toggle mechanismthrough the movable switch member serving to connect the stationarycontacts of the switch in the closed circuit position, therebysimplifying the tripping mechanism and eliminating unnecessary trippinglinkages.

In carrying the invention into effect, one of the so-called fixed orstationary contacts of the switch is mounted so as to have a limiteddegree of movement so that the tripping operation is accompanied by aninitial movement in the circuit closing direction of the movable switchmember coacting with the aforesaid contact, this initial and concurrentm-ovement causing collapse of the toggle mechanism and consequentopening movement of the breaker. The portion of the toggle mechanismoperatively connected to the movable switch member for actuating thesame into engagement with the stationary contact is preferably arrangedto continue its circuit closing movement after the switch H member hasengaged the stationary contact and come to rest, this continued movementcaus ng compression of a spring further biasing the switch member intoengagement with the stationary contact and thereby causing the aforesaidinitial movement of the switch member when a tripping device controllingthe movement of the stationary contact is actuated.

The control of the limited movement of the stationary contact may beeffected by a current responsive device as a'fusible element connectedin series with theswitch contacts or by means of an electromagneticcurrent responsive device. For the purpose of relieving the fusibleelement, when such is employed, of the tension necessary to maintain thestationary contact in position against the bias of the spring abovereferred to, there is preferably provided a toggle having one of itslinks pivoted to the stationary contact and another to a fixed point,the fusible element 35' passing over the common pivot of the two linksof the toggle thereby restraining collapse of the toggle. In the casewhere an electromagnetically controlled tripping device is used torestrain the movement of the stationary contact a toggle may alsoconveniently be employed the toggle being slightly overset in the closedposition of the switch, and collapse thereof is caused by actuation ofthe tripping device whereby limited movement of the stationary contacttakes place with consequent tripping of the toggle mechanism by thetripping impulse transmitted directly by the switch member. The movableswitch member may be pivotally connected at one end to one of thestationary contacts having no limited movement or may take the form of abridging member pivotally attached at its central portlon to an 0 ratingrod for making and breaking the circuit at the stationary contacts in awell known manner.

Our invention will be more fully set forth in the following descriptionreferring to the accompanying drawings, and the features of noveltywhichcharacterize our invention will be pointed out with particularityin the claims annexed to and forming a part of this specification.

Referring to the drawings, Fig. 1 is an elevational view, partly insection, of a cirthe tripping arrangement illustrated in Fig. 1

1; Fig. 3 is a view of the circuit breaker shown in Fig. 1 in the opencircuit position thereof; Fig. 4 is an elevational View, partly insection, of a modified form of trip )ing mechanism in the closed circuitposition ,Fig

5 is a similar view showing the apparatus in v the open circuitposition, and Fig. 6 is a view similar to Figs. 4 and 5 showin amodification of the movable switch mem er.

Referring to the arrangement shown in Figs. 1 to 3, there is illustratedan oil circuit breaker comprising a stationary contact 10 and aconducting element 11 carried at the lower ends of the insulatingbushings 12 and 13 respectively which extend through and are supportedin the housing 15 of the circuit breaker. The members 10 and 11 inclosed circuit position are electrically connected by the movable switchmember 16 carrying the movable contact coacting with contact 10 and inthe present instance pivoted at one end to the conducting element 11 andoperatively connected through the insulating operating rod 17 to theoperating mechanism likewise mounted within the housing 15. Theoperating mechanism comprises a bellcrank lever 18, to one arm of whichthe rod 17 is connected, pivotally mounted at 19 with respect to thehousing 15 and biased in a counterclockwise direction by the openingspring 20 which is connected at one end to the housing as at 21 and atthe other end to an arm of the bellcrank as at 22.

Movement of the bellcrank lever to cause opening and closing of thecircuit breaker is e ected throu h a toggle mechanism comprising thelindrs 23, 24 and 25. The link 23 is pivotally connected, as at 26, tothe arm 22 of the bellerank 18 and to the link 24 at the point 27. Thelink 25 is in turn pivotally mounted at 28 on the housing 15 and at itsother end is pivotally connected at 29 to the link 24. For the purposeof manually operating the circuit breaker the link 25 is provided with'a suitable operatin lever 30 mounted externally of the switc housin Forthe purpose of maintaining the tog e 23-2425 in a slightly oversetposition %or restraining the switch member in the closed circuitposition the link 24 is provided with a pin 31 arranged to be engaged bythe overhanging end 32 of the link 23.

The insulating rod 17 is suitably attached at its lower end to themovable switch member 16 and is resiliently connected at its upper endto the bellcrank 18. The up er extension 17 of the rod 17 extends thro g1 an opening in the pin 32, carried by the be lcrank 18 and is providedat its upper end with a collar or shoulder 33 between which and the pin32 a spring 34 is positioned so that the rod 17 has both sliding andpivotal movement with respect to the bellcrank 18.

The insulating rod 17 likewise is provided with an abutment 35 which,when the rod 17 is moved upwardly under the influence of spring 34, aswill be hereinafter described, enga es an extension 36 of the link 24cansing t e toggle comprising the links 23 and 24 to collapse.

The tripping device controlli limited movement of the contact 10 isiflustrated more clearly in Fig. 2 wherein the contact 10 is shownpivotally mounted at 37 on a collar 38 carried by an extension of theinsulating bushing 12. Mounted also upon the collar 38 is a to glecomprising links 39 and 40, the link 40% hanging en 41 of contact 10 andthe link 39 being plvotally connected at 42 to the collar 38, thetwolinks having a common pivotal connection 43. As illustrated in Fig. 2,the toggle is shown in the closed circuit position, the tripped or openeircuit position being illustrated by dotted lines. The contact 10 ismaintained in the position shown in Fig. 1 by a fusible element or link44 connected at 45 to-the corresponding conductor stud of the circuit:breaker. the link passing over the common pivot 43 of the toggle andattached at 46 to t .0 contact 10.

The operation of the circuit breaker is as follows: In the closedcircuit position illustrated in Fig. 1 the springs 20 and 34 are bothunder tension, the spring 20 tending to cause the bellcrank 18 to movein a counterclockwise direction to lower the rod 17 to open circuitposition, whereas the spring 34 tends to move the rod 17 in, an upwardor circuit closing direction. This later movement however is restrainedby the toggle 39-40 and the fusible element 44 which is placed undertension and prevents collapse of the tripping toggle. In res onse to apredetermined or abnormal circuit condition, as overload, the currentflowing through the fusible element 44 in series with the breakercontacts causes the fusible element to blow so that rupture thereofpermits the toggle 39-46 to collapse to the dotted line position underthe influence of the spring 34. The initial movement of the switchmember 16 in a clockwise direction thus instituted moves,the abutment 35sharply into engagement with the extension 36 of the toggle link 24causing collapse of the toggle and consequent opening movement of thebreaker under the influence of the opening spring 20 to the positionillustrated in Fig. 3.

The closing operation of the circuit breaker must be preceded byreplacement of the fusible element. whereupon the toggle 2324 may bestraightened by rotating the operating handle 30 in a counterclockwisedirection and then moving it in a clockwise direction to rotate thebellcrank member 18 clockwise. During this movement the switch member 16engages the contact 10 so that subsequent movement of the bellcrankcauses only comin pivotally connected to the overspring 34.

Referring now to Figs. 4 and 5, the arrangement shown is generallysimilar to that shown in Figs. 1 and 2, and does not require detaileddescription except insofar as the tripping mechanism is concerned. Inthis case, the tripping device is controlled electromagnetically insteadof by a fusible element,

,as in Figs. 1 and 2. The contact 10 is pivotally mounted on the member47 carried by the insulating member 48 at the lower end of the bushing12. The member 48 furthermore carries a magnet 49 having a coil 50 andan armature 51 of bellcrank shape, pivoted at 52 to the member 47. Thecoil 50 is included in series with the switch contacts in the circuitcontrolled by the breaker. The counterclockwise rotation of the contact10 about its pivot is restrained by the toggle comprising links 52 and53 which. in the closed position of the circuit breaker, are slightlyoverset, shown. ()n a predetermined overload occurring in the circuit,armature 51 is attracted to the magnet 49, and the arm 54 of thearmature 51 strikes the common pivot of the links 52 and 53, causing thecollapse of the toggle and the opening of the breakerinthe mannerdescribed in connection with Figs. 1 and 2 The position of the variousparts of the circuit breaker in the tripped-open position are as shownin Fig. 5. On the opening of the circuitbreaker, the armature 51 is nolonger attracted, thereby permitting the contact 10 to rotate in aclockwise direction under the action of gravity so that the togglecomprising links 52 and 53 becomes straightened, as shown iuFig. 5.

In Fig. '6 there is shown an arrangement having an electromagneticallyoperated tripping device similar to that described in connection withFigs. 4 and 5. The only difference in this particular construction isthat instead of the switch member 16 being pivoted to the member 11, itis pivotally arranged upon the insulating rod 17. In this case, upon thetripping open of the circuit breaker by the limited movement of contact10, the switch member 16 is permitted to slide on the contact surfacesof the contact 10 and member 11 about its fulcrum on the insulating rod17 to the position shown in dotted lines in Fig.

6, whereupon the breaker is tripped open as described in connection withFigs. 4 and Preferably. the switch member 16 is arranged been shown ascomprising upper and lower metallic members attached through aninsulater which may be of porcelain or any other suitable material. Itis to be understood, however, that any: other construction of theinsulating rod 17 is permissible provided the switch member is insulatedfrom the toggle operating mechanism. The various links of the toggleoperating mechanism usually comprise a pair of parallel members suitablyspaced from one another, spacing members serving to provide thenecessary pivot points about which the various links co-act.

It is also to be understood that the invention has been described onlyin connection with a single phase breaker, but the invention may beemployed in connection with polyphase circuits. In this case thetripping open of the circuit breaker on any one phase may be arranged ina well known manner to trip open the breaker situated in the otherphases of the circuit.

It should be understood that our invention is not limited to specificdetails of construction and arrangement thereof herein illustrated, andthat changes and modifications may occur to one skilled in therartwithout departing from the spirit of our invention.

What we claim as-new and desire to secure by Letters Patent of theUnited States, is:

1. An electric circuit breaker comprising a movable switch member,coacting contacts controlled thereby, operating mechanism restrainingsaid switch member in the closed circuit position, and means responsive.to an abnormal circuit condition causing an initial movement of saidswitch member in the switch closing direction, said initial movementcausing collapse of said operating mechanism and circuit openingmovement of said switch member.

2. An electric circuit breaker comprising a movable switch member.contacts coacting therewith, an operating toggle restraining said switchmember in the closed circuit position, and means responsive to anabnormal circuit condition causing an initial movement of said switchmember in a closing direction independently of said operating toggle,said initial moy'ement causing collapse of said operating toggle andcircuit opening movement of said switch member.

3. An electric circuit breaker comprising ment of said switch member inresponse to said limited movement.

4. In an electric circuit breaker including a movable switch member, acooperating contact mounted for limited movement and operating mechanismcollapsible to cause cirsaid resilient connection, and means actuated inresponse to said initial movement of said switch member causing collapseof said mechanism and circuit opening movement of said switch member.

5. Trippin mechanism for an electric circuit breaker aving a movableswitch member, operating mechanism collapsible to cause circuit openingmovement of said member and a contact coacting with said switch member,said contact mounted for limited movement, comprising a currentresponsive device normally maintaining said contact in a predeterminedposition, means resiliently biasing said switch member into engagementwith said contact tending to move said contact into another position,release of said contact in response to actuation of said currentresponsive device causing limited movement of said switch memberindependently of said operating mechanism under influence of saidbiasing means, and means connected to said switch member directlycausing trippingof said collapsible mechanism and circuit openingmovement in response to said.- limited movement.

6. An electric circuit breaker comprising a movable switch member, acontact mounted for limited movement coactin therewith, overset toggleoperating mechanism restraining said switch member in closed circuitposition, an o ening spring for biasing said switch mem r to opencircuit position in response to tripping of said toggle mechanism, meansinterconnecting said switch member and operating mechanism resilientlybiasing said switch member independently of said opening spring intoengagement with said contact in the closed circuit position,

means arranged to release said contact in response to an abnormalcircuit condition, said resilient biasing means thereby causing aninitial movement of said switch member in the circuitclosing directionindependently oi said toggle operating mechanism, and means connected tosaid switch member causing tripping of said mechanism and circuitopening movement in response to said initial movement. r

7. An electric circuit breaker comprising a movable switch member and acontact mounted for limited movement coacting therewith, toggle 0 ratingmechanism 0 ratively connected rough an insulating rod to said switchmember, said toggle mechanism having a resilient connection with saidrod arranged so that said resilient connection is stressed in thecircuit closing operation, an opening spring tending to bias said togglemechanism towards open circuit position, and tripping means comprising acurrent responsive device coactin with said con tact arranged so thatactuation of said device releases said contact for limited movement andcauses corres nding movement of said switch member t rough saidresilient connection, and a member connected to said rod causingtripping of said toggle in response to said movement. I I

8. In an electric circuit breaker including a movable switch member anda contact coacting therewith, said contact mounted for limited movement,and o ratin mechanism colla sible to cause circuit opening movement ofsaid switch member, tripping means comprising a fusible element normallyrestraining said contact in a redetermined position, means resilientlybiasing said switch member into engagement with said contact arranged sothat rupture of said fusible element causes a release of. said contactand an initial movement of said switch member independently of saidoperating mechanism, and means .connected ,tosaid switch member causingcolla of said operating mechanism and circuit opening movement inresponse to said initial movement.

9. In an electric circuit breaker including a movable switch member anda contact coacting therewith, said contact mounted for limited ivotalmovement and toggle operating mec anism collapsible under the influenceof an opening spring to cause circuit opening movement of said switchmember, tripping means for said toggle mechanism comprising a fusibleelement connected in serigs with the circuit breaker normallyrestraining movement of said contact, an underset toggle connected tosaid contact and engaged by said fusible element arranged so that therestraining force is borne mainly by said toggle, a resilient connectionbetween said switch member and toggle mechanism stressed in the closedcircuit position to bias said switch member into engagement with saidcontact whereby rupture of said fusible element causes release of saidcontact and an initial movement of said switch member through saidresilient connection, and means actuated in response to said initialmovement of said switch member directly causing tripping of said togglemechanism and circuit opening movement.

10. In an electric circuit breaker includin a movable switch member, acontact mounte for limited movement coacting therewith, an operatingtoggle having a resilient connection with said switch member, saidresilient connection biasing said switch member into engagement withsaid contact in the closed circuit position of said member, and anelectromagnetic current responsive device coacting with said contactarranged so that actuation of said device releases said contact andcauses limited movement of said switch member in the closing directionunder influence of said resilient connection, and means connected tosaid switch member causing tripping of said operating toggle in responseto said movement.

11. An electric circuit breaker comprising a pair of coacting contacts,operating mechanism for controlling said contacts, means responsive toan abnormal circuit condition causing initial and concurrent movement ofsaid contacts, and means responsive to the aforesaid initial movement ofsaid contacts causing circuit opening movement of said operatingmechanism.

12. An electric circuit breaker comprising a movable switch member,coacting contacts controlled thereby, operating mechanism including atripping toggle for restraining said switch member in the closed circuitposition, and means responsive to an abnormal circuit condition causingan initial movement of said switch member, said switch member trippingsaid toggle during said movement causing circuit opening movement ofsaid operating mechanism and switch member.

In witness whereof, we have hereunto set our hands.

HENRY TRENCHAM.- HERBERT C. HEATH.

